lkml.org 
[lkml]   [2007]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Date
    Subject[PATCH 13/22 take 3] UBI: accounting unit
    diff -auNrp tmp-from/drivers/mtd/ubi/account.c tmp-to/drivers/mtd/ubi/account.c
    --- tmp-from/drivers/mtd/ubi/account.c 1970-01-01 02:00:00.000000000 +0200
    +++ tmp-to/drivers/mtd/ubi/account.c 2007-03-14 17:15:50.000000000 +0200
    @@ -0,0 +1,233 @@
    +/*
    + * Copyright (c) International Business Machines Corp., 2006
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
    + * the GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public License
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
    + *
    + * Author: Artem B. Bityutskiy
    + */
    +
    +/*
    + * UBI accounting unit.
    + *
    + * This unit is responsible for maintaining physical eraseblock accounting to
    + * prevent overcommitment.
    + */
    +
    +#include <linux/err.h>
    +#include "ubi.h"
    +
    +/* The lowest number PEBs reserved for bad PEB handling */
    +#define MIN_RESEVED_PEBS 1
    +
    +/**
    + * ubi_acc_reserve - reserve a number of physical eraseblocks.
    + *
    + * @ubi: the UBI device description object
    + * @pebs: how many physical eraseblocks to reserve
    + *
    + * This function returns zero in case of success and %-ENOSPC if there is no
    + * enough physical eraseblocks.
    + */
    +int ubi_acc_reserve(struct ubi_info *ubi, int pebs)
    +{
    + ubi_assert(pebs > 0);
    +
    + spin_lock(&ubi->acc.lock);
    + ubi_assert(ubi->acc.avail_pebs >= 0);
    + if (pebs > ubi->acc.avail_pebs) {
    + dbg_err("not enough PEBs: requested %d, available %d",
    + pebs, ubi->acc.avail_pebs);
    + spin_unlock(&ubi->acc.lock);
    + return -ENOSPC;
    + }
    + ubi->acc.avail_pebs -= pebs;
    + ubi->acc.rsvd_pebs += pebs;
    + spin_unlock(&ubi->acc.lock);
    + return 0;
    +}
    +
    +/**
    + * ubi_acc_free - free a number of reserved physical eraseblocks.
    + *
    + * @ubi: the UBI device description object
    + * @pebs: how many physical eraseblocks to free
    + */
    +void ubi_acc_free(struct ubi_info *ubi, int pebs)
    +{
    + ubi_assert(pebs > 0);
    +
    + spin_lock(&ubi->acc.lock);
    + ubi_assert(pebs <= ubi->acc.rsvd_pebs);
    + ubi->acc.rsvd_pebs -= pebs;
    + ubi->acc.avail_pebs += pebs;
    + ubi_assert(ubi->acc.rsvd_pebs >= 0);
    + spin_unlock(&ubi->acc.lock);
    +}
    +
    +/**
    + * calculate_beb_rsvd_max - calculate how many PEBs must be reserved for bad
    + * eraseblock handling.
    + *
    + * @ubi: the UBI device description object
    + */
    +static void calculate_beb_rsvd_max(struct ubi_info *ubi)
    +{
    + ubi->acc.beb_rsvd_max = ubi->io.good_peb_count/100;
    + ubi->acc.beb_rsvd_max *= CONFIG_MTD_UBI_BEB_RESERVE;
    + if (ubi->acc.beb_rsvd_max < MIN_RESEVED_PEBS)
    + ubi->acc.beb_rsvd_max = MIN_RESEVED_PEBS;
    +}
    +
    +/**
    + * ubi_acc_peb_marked_bad - a physical eraseblock was marked as bad,
    + * re-calculate accounting.
    + *
    + * @ubi: the UBI device description object
    + */
    +void ubi_acc_peb_marked_bad(struct ubi_info *ubi)
    +{
    + int need;
    +
    + ubi_assert(ubi->acc.beb_rsvd_pebs >= 0);
    +
    + if (!ubi->io.bad_allowed)
    + return;
    +
    + spin_lock(&ubi->acc.lock);
    + if (ubi->acc.beb_rsvd_pebs == 0) {
    + ubi_warn("no reserved physical eraseblocks");
    + ubi_ro_mode(ubi);
    + }
    + calculate_beb_rsvd_max(ubi);
    + ubi->acc.beb_rsvd_pebs -= 1;
    + need = ubi->acc.beb_rsvd_max = ubi->acc.beb_rsvd_pebs;
    + if (need > 0) {
    + int alloc;
    +
    + alloc = ubi->acc.avail_pebs >= need ? need
    + : ubi->acc.avail_pebs;
    + ubi->acc.avail_pebs -= alloc;
    + ubi->acc.rsvd_pebs += alloc;
    + ubi->acc.beb_rsvd_pebs += alloc;
    + }
    + if (ubi->acc.beb_rsvd_pebs == 0)
    + ubi_warn("last PEB from the reserved pool was used");
    + spin_unlock(&ubi->acc.lock);
    +}
    +
    +/**
    + * acc_info_check - check sanity and consistency of accounting information.
    + *
    + * @ubi: the UBI device description object
    + *
    + * We do not trust data read from the flash media and we check that the
    + * accounting information is consistent, because it is formed using on-flash
    + * data. This function returns zero if everything is fine and %-EINVAL if some
    + * inconsistency was found.
    + */
    +static int acc_info_check(const struct ubi_info *ubi)
    +{
    + if (ubi->acc.avail_pebs < 0 || ubi->acc.rsvd_pebs < 0)
    + goto bad;
    +
    + if (ubi->acc.avail_pebs > ubi->io.good_peb_count) {
    + dbg_err("bad avail_pebs");
    + goto bad;
    + }
    +
    + if (ubi->acc.rsvd_pebs > ubi->io.good_peb_count ||
    + ubi->acc.rsvd_pebs < ubi->vtbl.vol_count) {
    + dbg_err("bad rsvd_pebs");
    + goto bad;
    + }
    +
    + if (ubi->acc.avail_pebs + ubi->acc.rsvd_pebs !=
    + ubi->io.good_peb_count) {
    + dbg_err("accounting error");
    + goto bad;
    + }
    +
    + return 0;
    +
    +bad:
    + ubi_err("accounting check failed");
    + dbg_err("avail_pebs %d, rsvd_pebs %d, ubi->io.good_peb_count %d",
    + ubi->acc.avail_pebs, ubi->acc.rsvd_pebs,
    + ubi->io.good_peb_count);
    + return -EINVAL;
    +}
    +
    +/**
    + * ubi_acc_init_scan - initialize the accounting unit using scanning
    + * information.
    + *
    + * @ubi: the UBI device description object
    + * @si: a pointer to the scanning information
    + *
    + * This function returns zero in case of success and a negative error code in
    + * case of failure.
    + */
    +int ubi_acc_init_scan(struct ubi_info *ubi, struct ubi_scan_info *si)
    +{
    + int err, i;
    + const struct ubi_vtbl_vtr *vtr;
    +
    + dbg_uif("initialize the accounting unit");
    +
    + spin_lock_init(&ubi->acc.lock);
    +
    + for (i = 0; i < UBI_INT_VOL_COUNT; i++) {
    + vtr = ubi_vtbl_get_vtr(ubi, UBI_INTERNAL_VOL_START + i);
    + ubi_assert(!IS_ERR(vtr));
    + ubi->acc.rsvd_pebs += vtr->reserved_pebs;
    + }
    +
    + for (i = 0; i < ubi->vtbl.vt_slots; i++) {
    + vtr = ubi_vtbl_get_vtr(ubi, i);
    + if (IS_ERR(vtr))
    + continue;
    + ubi->acc.rsvd_pebs += vtr->reserved_pebs;
    + }
    +
    + ubi->acc.rsvd_pebs += si->alien_peb_count;
    + ubi->acc.avail_pebs = ubi->io.good_peb_count - ubi->acc.rsvd_pebs;
    +
    + if (ubi->io.bad_allowed) {
    + calculate_beb_rsvd_max(ubi);
    +
    + if (ubi->acc.avail_pebs < ubi->acc.beb_rsvd_max) {
    + /* No enough free physical eraseblocks */
    + ubi->acc.beb_rsvd_pebs = ubi->acc.avail_pebs;
    + ubi_warn("cannot reserve enough PEBs for bad PEB "
    + "handling, reserved %d, need %d",
    + ubi->acc.beb_rsvd_pebs, ubi->acc.beb_rsvd_max);
    + } else
    + ubi->acc.beb_rsvd_pebs = ubi->acc.beb_rsvd_max;
    +
    + ubi->acc.avail_pebs -= ubi->acc.beb_rsvd_pebs;
    + ubi->acc.rsvd_pebs += ubi->acc.beb_rsvd_pebs;
    + }
    +
    + /* Check accounting information sanity and consistency */
    + err = acc_info_check(ubi);
    + if (err)
    + return err;
    +
    + dbg_uif("accounting unit is initialized");
    + dbg_uif("avail_pebs %d rsvd_pebs %d, max_volumes %d",
    + ubi->acc.avail_pebs, ubi->acc.rsvd_pebs, ubi->vtbl.vt_slots);
    +
    + return 0;
    +}
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/
    \
     
     \ /
      Last update: 2007-03-14 16:47    [W:3.112 / U:0.248 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site